Computer systems generate image data representative of imaged bodies. The imaged bodies may be displayed on a display device of the computer system. Some types of computer systems can generate multi-dimensional image data. For example, some ultrasound computer systems can generate both two-dimensional image slices and three (or four) dimensional images or videos for viewing by operators of the computer systems.
The images displayed by the display device may be manipulated by an operator in multiple ways to change display of one or more components of the images. The user may activate a user interface or an input device, such as an electronic mouse or a track ball, to manipulate the images. As one example, the user may activate the input device to move a cursor to a target location on the screen of the display device. The cursor is linked to the input motion by a predefined constant distance ratio of the computer system such that the cursor moves across the display device at a predefined speed. When the user moves a distance A, the cursor on the display device moves a distance B. However, this constant distance ratio is often not suitable for different applications and the operation becomes cumbersome. If the ratio A/B is too low, then the cursor moves erratically over the display device. If the ratio A/B is too high, the user has to roll the electronic mouse or track ball multiple times to reach the target on the screen.
As another example, the user may manipulate the images by activating a slider control on the display device to change the value of a parameter. For example, the slider control may be used to change the magnification of the image, to change the speed of rotation of a multi-dimensional image, to move to a different page of a document or file, to change a ratio between a magnification of a first image and a magnification of a second image, to change a position of a displayed object on the display device, to change the speed of movement of a cursor on the display device, or to change the scale of the slider control. Using the input device or an appendage of the user touching the display device, the user moves an indicator element along the slider control. However, the size of the display device is often limited and the user cannot accurately adjust the indicator element on the slider control with a finger. For example, minimal movement with the finger may result in a change of the value of the slider control that is greater than intended.